Dissociation of achromatic and chromatic processing of spatial form and temporal modulation by the titration method

Using a titration method to attempt to silence the achromatic contrast subsystem, we tested the assumption that an equiluminant chromatic pattern does not stimulate the physiological achromatic contrast subsystem. We also examined the question whether contrast threshold is entirely or even partially determined by the chromatic contrast subsystem at equiluminance. We report a method for demonstrating when contrast threshold is entirely determined by the chromatic contrast subsystem.